[v2] mtd: atmel_nand: make ecc parameters same as definition

Commit Message

Bo Shen June 12, 2014, 7:58 a.m. UTC

If the ecc parameter is not the same as definition, when the
mtd core check these parameters, it will give the error result.

Take the following as an example:

Calculate how many bits can be corrected in one page.
According to the ecc parameters definition,

one page correct bits = (mtd->writesize * ecc->strength) / ecc->size

take the following use case as an example:
mtd->writesize = 2048 bytes
ecc->strength = 4 bytes (for 512 bytes)

before this patch, the ecc->size = 2048, so the result is 4 bytes.
after this patch, the ecc->size = 512, so the result is 16 bytes.

So, align the ecc parameters the same as definition to correct
this kind of error.

Signed-off-by: Bo Shen <[e-mail]>
Acked-by: Josh Wu <[e-mail]>
---
Changes in v2:
  - Enhancement the commit message.

 drivers/mtd/nand/atmel_nand.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

Comments

Brian Norris July 22, 2014, 2:56 a.m. UTC | #1

On Thu, Jun 12, 2014 at 03:58:45PM +0800, Bo Shen wrote:
> If the ecc parameter is not the same as definition, when the
> mtd core check these parameters, it will give the error result.
> 
> Take the following as an example:
> 
> Calculate how many bits can be corrected in one page.
> According to the ecc parameters definition,
> 
> one page correct bits = (mtd->writesize * ecc->strength) / ecc->size
> 
> take the following use case as an example:
> mtd->writesize = 2048 bytes
> ecc->strength = 4 bytes (for 512 bytes)
> 
> before this patch, the ecc->size = 2048, so the result is 4 bytes.
> after this patch, the ecc->size = 512, so the result is 16 bytes.
> 
> So, align the ecc parameters the same as definition to correct
> this kind of error.
> 
> Signed-off-by: Bo Shen <[e-mail]>
> Acked-by: Josh Wu <[e-mail]>
> ---
> Changes in v2:
>   - Enhancement the commit message.

Pushed to l2-mtd.git. Thanks!

Brian

Patch

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 4ce181a..4f5348f 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -861,12 +861,11 @@  static int pmecc_correction(struct mtd_info *mtd, u32 pmecc_stat, uint8_t *buf,
 {
 	struct nand_chip *nand_chip = mtd->priv;
 	struct atmel_nand_host *host = nand_chip->priv;
-	int i, err_nbr, eccbytes;
+	int i, err_nbr;
 	uint8_t *buf_pos;
 	int total_err = 0;
 
-	eccbytes = nand_chip->ecc.bytes;
-	for (i = 0; i < eccbytes; i++)
+	for (i = 0; i < nand_chip->ecc.total; i++)
 		if (ecc[i] != 0xff)
 			goto normal_check;
 	/* Erased page, return OK */
@@ -928,7 +927,7 @@  static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
 	struct nand_chip *chip, uint8_t *buf, int oob_required, int page)
 {
 	struct atmel_nand_host *host = chip->priv;
-	int eccsize = chip->ecc.size;
+	int eccsize = chip->ecc.size * chip->ecc.steps;
 	uint8_t *oob = chip->oob_poi;
 	uint32_t *eccpos = chip->ecc.layout->eccpos;
 	uint32_t stat;
@@ -1169,8 +1168,7 @@  static int atmel_pmecc_nand_init_params(struct platform_device *pdev,
 		goto err;
 	}
 
-	/* ECC is calculated for the whole page (1 step) */
-	nand_chip->ecc.size = mtd->writesize;
+	nand_chip->ecc.size = sector_size;
 
 	/* set ECC page size and oob layout */
 	switch (mtd->writesize) {
@@ -1185,18 +1183,20 @@  static int atmel_pmecc_nand_init_params(struct platform_device *pdev,
 		host->pmecc_index_of = host->pmecc_rom_base +
 			host->pmecc_lookup_table_offset;
 
-		nand_chip->ecc.steps = 1;
+		nand_chip->ecc.steps = host->pmecc_sector_number;
 		nand_chip->ecc.strength = cap;
-		nand_chip->ecc.bytes = host->pmecc_bytes_per_sector *
+		nand_chip->ecc.bytes = host->pmecc_bytes_per_sector;
+		nand_chip->ecc.total = host->pmecc_bytes_per_sector *
 				       host->pmecc_sector_number;
-		if (nand_chip->ecc.bytes > mtd->oobsize - 2) {
+		if (nand_chip->ecc.total > mtd->oobsize - 2) {
 			dev_err(host->dev, "No room for ECC bytes\n");
 			err_no = -EINVAL;
 			goto err;
 		}
 		pmecc_config_ecc_layout(&atmel_pmecc_oobinfo,
 					mtd->oobsize,
-					nand_chip->ecc.bytes);
+					nand_chip->ecc.total);
+
 		nand_chip->ecc.layout = &atmel_pmecc_oobinfo;
 		break;
 	case 512: